Rail vehicle slack adjusters may be divided into two main groups having one or two nuts, respectively, in non-self-locking engagement with the spindle in order to perform the function of adjusting the slack between a brake block or pad and a tread of a wheel or a brake disc to a an intended value.
The present invention relates to an adjuster of the one-nut-type.
There are numerous examples of such adjusters, typical examples being disclosed by EP-A-0 165 641, DE-A-23 16 822, EP-A-0 174 690, U.S. Pat. No. 4,036,332, and DE-A-28 30 361 (without any specific order).
A basic example of a one-nut-adjuster built-into a so called brake unit with considerable commercial success is shown in U.S. Pat. No. 3,744,596. This adjuster, however, has certain drawbacks, of which the most important one is that it contains a powerful spring needed for its adjusting function and creating a considerable counter-force at brake application. Also, its spindle and nut is combined into one unit creating an unnecessarily great rotating mass.
Another one-nut-adjuster without these drawbacks is shown in U.S. Pat. No. 4,138,002, which is regarded as the closest prior art. However, this prior adjuster has other drawbacks, such that a compression spring therein causes a counter-force (which, however, is smaller than in U.S. Pat. No. 3,744,596) at brake application and that the provision of two internal clutch surfaces in the member corresponding to the driver element causes great manufacturing difficulties with accompanying greater expenses.